The Pitzer model
The functions in pytzer.model
use the Pitzer model to calculate various solution properties for a fixed composition.
All examples use the import convention:
import pytzer as pz
Arguments
All the main functions in pytzer.model
have the same syntax, and they are all aliased at the top level, for example:
Gibbs_nRT = pz.model.Gibbs_nRT(solutes, **params)
Gibbs_nRT = pz.Gibbs_nRT(solutes, **params)

The argument
solutes
is anOrderedDict
containing the molality (in mol/kg) of each solute in the solution. Each molality must be a single scalar value. 
The other kwargs contained in
params
can be generated forsolutes
using theParameterLibrary
methodget_parameters()
.
The result is always either a single scalar value or an OrderedDict
with the same keys as in the solutes
.
Functions
The properties that can be calculated using the syntax above are:
Excess Gibbs energy
Excess Gibbs energy of the solution.
Gibbs_nRT = pz.Gibbs_nRT(solutes, **params)
Solute activity coefficients
Chemical activity coefficients for every solute or their natural logarithms.
activity_coefficients = pz.activity_coefficients(solutes, **params)
log_activity_coefficients = pz.log_activity_coefficients(solutes, **params)
Water activity
Chemical activity of the solvent (water) or its natural logarithm.
activity_water = pz.activity_water(solutes, **params)
log_activity_water = pz.log_activity_water(solutes, **params)
Osmotic coefficient
Osmotic coefficient of the solution.
osmotic_coefficient = pz.osmotic_coefficient(solutes, **params)